The present invention relates to a projection control system, a projector, and a projection control method capable of deriving a projection angle based on sensing information and adjusting a projection direction or the like based on the projection angle.
When a projector projects an image onto a screen or the like, image distortion (keystone distortion) occurs depending on the angle formed by a projection target area on the screen or the like and projection light from the projector.
In this case, the projector performs image processing of eliminating image distortion by software correction.
The software correction can be performed at low cost, but causes the image quality to deteriorate.
Therefore, a method of eliminating image distortion by hardware correction has been proposed aiming at improving the image quality. In an automatic image position adjustment method for a projector disclosed in JP-A-2000-241874, a specific test pattern is projected onto a screen from a projector, the image of the test pattern projected onto the screen is sensed by using a monitor camera, and the image data of the sensed test pattern is analyzed to adjust the focus of the projector. The automatic image position adjustment method disclosed in JP-A-2000-241874 projects a quadrilateral solid white image onto the screen as the image of the test pattern, and detects the position of the screen in the solid white image sensed by using the monitor camera. The projected image is expanded or reduced by using a zooming function of the projection lens until the projected image reaches the detected endpoints of the screen, and the angle of elevation of the projection lens is adjusted to display the projected image at the center of the screen. The automatic image position adjustment method disclosed in JP-A-2000-241874 adjusts keystone distortion of the projected image by means of software or hardware (optically) by calculating the keystone distortion adjustment value from the positions of the endpoints of the screen and the positions of the endpoints of the solid white image.
However, processing takes time when using this method of adjusting the angle of view by expanding or reducing the projected image by using the zooming function of the projection lens until the projected image reaches the detected endpoints of the screen as disclosed in JP-A-2000-241874. Moreover, the method disclosed in JP-A-2000-241874 cannot be applied when the aspect ratio of the screen differs from the aspect ratio of the projected image. JP-A-2000-241874 adjusts the image display position by adjusting the angle of elevation of the projection lens so that the projected image is displayed at the center of the screen. However, JP-A-2000-241874 does not disclose detailed processing.